Para-t-butyl-{60 -methylstyrene polymers

ABSTRACT

High molecular weight homopolymers of t-butyl-alphamethylstyrene and lubricating oil containing them.

United States Patent Bcskai 1 1 0a. 14, 1975 [54] PARA-T-BUTYL-oe-METHYLSTYRENE [56 References Cited POLYMERS UNITED STATES PATENTS [75] Inventor; Robert Bacskai,- Kensington, Calif. 2,448,976 9/ 1948 Heiligmann 260/935 S 2,479,618 8/1949 Hersberger 260/93.5 S Asslgneei Research Company, San 3,139,416 6/1964 Lumb et a1. 260/93.5 s Franclsco, Cahf. 3,318,813 5/1962 McCormick 252/59 3,379,784 4/1968 Kahn 260/669 [22] May 1971 3,423,382 1/19'69 Chibnik 260/93.5 [21] Appl. No; 143,595

Primary Examiner-Paul R. Mich] Related Application Data Attorney, Agent, or FirmJ. A. Buchanan, Jr.; John [62] Division of Ser. No. 886,382, Dec. 18, 1969, Pat. No. Stoner Russell p i 57 ABSTRACT [52] US. Cl. 260/93.5 R; 260/93.5 A 1 51 1111.0. C08F 112/12 mdwfla [58] Field of Search 26O/669 R 669 p 93 5 S t-butyl-a1pha-methy1styrene and lubncatmg 01] containing them.

1 Claim, No Drawings PARA-T-BUTYL-a-METHYLSTYRENE POLYMERS CROSS-REFERENCE TO RELATED APPLICATION This application is a divisionof U.S. patent application Ser. No. 886,382, filed Dec. 18, 1969,.issued Feb. 15, 1 972, as U.S. Pat. No. 3,642,636.

BACKGROUND O THE INVENTION This invention relates to novel high molecular weight homopolymers of para-t-butyl-alpha-methylstyrene and lubricating oilscontaining them as viscosity index improvers. I

I-Iigh molecular weight hydrocarbon polymers are useful in a variety of applications. They are widely used as thickeners in surface coating compositions such as paint and the like. They are also used as thickeners for fuel compositions or as viscosity index improvers in lubricating oil compositions. A 1

Polymers of t-butylstyrene have recently been suggested as viscosity: index 'improvers as illustrated by U.S. Pat. No. 3,318,813 issued May 9, 1967 to McCormick and Nummy.

SUMMARY OF THE'INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENTS The synthesis of para-t-butyl-alpha-methylstyrene is carried out in accordance with the following scheme:

CO-CH:

AlCl

n c-c-cn The above preparation of the intermediate para-tbutyl-acetophenone is; achieved with 95% purity by the method of Butler, Ferstandig and Clark reported in the Journal of the-American Chemical Society, Vol. 76, page 1906, in 1954. Using the method of Hermans,

Knaeps and Van der Eycken reported in Chemical Ab stracts vol. 54, page 759211, in 1960, the acetophenone is converted to the carbinol, which is then dehy= drated to yield the para-t-butyl-alpha-methylstyrene in 98% purity. 1' '1 The parat-butyl alpha-methylstyrene is polymerized readily with cationic or anionic catalysts of known types. Solventsare used in the reaction to facilitate mixing and handling where desired. Pressure and temperature of the "reactionare not critical butcooling is generally desirable to control the rate of polymerization.

The homopolymers of para-t-butyl-alphamethylstyrene of the invention have average molecular weights of at least about 20,000 as determined by standard light-scattering methods. For present purposes the preferred polymers have average molecular weights in the range of from about 50,000 to about 1,000,000 and a solubility in mineral lubricating oil of 0.1% by weight.

The following examples are further illustrative of the homopolymers of para-t-butyl-alpha-methylstyrene according to this invention. Unless otherwise specified,

the proportions in the illustrative examples are on a I weight basis.

EXAMPLE I In this example the polymer of para-t-butyl-alphamethylstyrene was prepared by cationic polymeri zation. Into a 200-ml, 3-necked flask there was introduced 60 ml'ofCh Cl and 10 g of p-tert-butyl-a V methylstyrene. The flask was equipped with thermometer, drying tube, and a side arm for the introduction of catalyst. The reaction mixture was cooled to 78fC, and 0.36 g of BF .Et O was added dropwise in 25 minutes. The reaction mixture became viscous;'ahd polymer precipitated. After maintaining the reaction mix ture at 78C for an additional 35 minutes, a few drops of methanol were added. The contents of the flaskw ere poured into 500 ml'of methanol, and the precipitate was filtered and subsequently dried at C in vacuum.

Yield: 9.60 g (96% of theory) Specific viscosity: nsp/C 0.56 (25C, C H 0.1

g/100 ml) EXAMPLE II EXAMPLE III In this example the polymer of para-t-butyl-alphamethylstyrene was prepared by anionic polymerization.

This polymer was prepared by a method developed for the polymerization of alpha-methylstyrene by Brauh,

Heufer, .Iohnsen and Kolbe, Bunsen Ges. Phys. Chem. Ber., Vol. 68, page 959, 1964. The catalyst used was prepared by melting together, in a'nitrogen atmosphere, 2.71 g potassium and 1.36 g sodium'in 100 ml n-heptane. I i

A 3-necked, 250ml flask equipped with stirrer, thermometer, N inlet tube, and drying tube was charged with 9.80 g of freshly distilled p-tert-butyl-alphamethylstyrene and 50 ml of tetrahydrofuran (distilled at least about carefully with more methanol, and the reaction mixture was poured into a solution of 500 ml of methanol and 5 ml of concentrated-.HCI. The precipitated polymer was filtered, washed with methanol, and dried at 70C.

Yield: 7.37 g (75.2 of theory) Specific viscosity: nsp/C 0.08 (25C, C H 0.1

v g/ 100 ml) EXAMPLE IV In this example the polymer of alpha-methylstyrene produced by anionic polymerization was prepared for comparative purposes.

Yield: 9.74 g (96.8% of theory) Specific viscosity: nsp/C 0.22 (25C, C 11 0.1

' g/l ml) The polymers of para-t-butyl alpha-methylstyrene of this invention are oil soluble. This is intended to mean they are soluble in conventional mineral oils and other oil compositions in a concentration of at least about 0.1% by weight based on the total composition.

In the lubricating oil compositions of this invention the para-t-butyl-alpha-methylstyrene polymer is used with lubricating oil base in an amount sufficient to raise the viscosity index ofthe base lubricating oil. Ordinarily amounts of the polymer of from about 0. 1% to about 15% by weight are satisfactory for this purpose. In view of the excellent solubility characteristics of the polymer, afurther feature ofthe invention lies in the preparation of lubricating oil concentrates containing percentages of polymers of up to about 75% by weight.

The base oil in the lubricant composition of the inpreferred,-since they show the greatest viscosity and stability improvement.

ent invention may also contain still other additives of conventional types, such as pour-point depressants, oiliness and extreme pressure agents, anti-oxidants, blooming agents and the like. Other types of deter-, gents, such as metal salts, may also be employed where ash formation is not a problem.

Illustrative lubricant compositions of the aforementioned types containing additives other than the polymeric additive may include, for example, from about 0.1 to about 10% by weight of alkaline earth metal, higher alkyl phenate detergent and wear reducing agents such as the calcium alkylphenate having mixed alkyl groups of 12 to 15 carbon atoms. They may also include from about 0.1 to 10% by weight of organic thiophosphate corrosion and high-temperature oxidation inhibitors, such as the reaction product of pinene and P 8 the reaction product of polybutene and P 8 and the bivalent metal dihydrocarbon dithiophosphates, zinc butyl amyl dithiophosphate and zinc di- (tetradecylphenyl) dithiophosphate. Metal salt detergents in amounts from about 0.1 to 10% which may also be used are the calcium petroleum sulfonates of the oil soluble mahogany type and the calcium naphthenates.

withthis invention are shown in various tests. In thesetests the viscosities of the compositions are determined and the viscosity index calculated by the Standard ASTM Method D567-41.

In the tests, 2.8% by weight of the polymer is dissolved in 130 Neutral Oil, which is a California paraffin base oil having a viscosity of 130 SSU at 100F. This base oil ordinarily has a viscosity index of 89.

The tests of the polymer of para-t-butyl-alphamethylstyrene in comparison with para-t-butylstyrene vention is any oil of lubricating viscosity. Thus, the base 40 are reported in the following table:

TABLE Polymer of Polymer para-tof parabutyl-a- RPM 130 t-butylmethyl- Neutral styrene styrene oxidizability 2.71 2.51 2.34 Viscosity Viscosity,100F, SUS 130.8 386.1 341.7 Viscosity,2 1 0F,SUS Before g 41.53 71.09 62.9 V.1. Oxidation 89 140 133 Viscosity, 100F,SUS 169 317.2 344.7 Viscosity.210F,SUS After 43.55 58.96 60.85 V.1. Oxidation 127 126 oil can be a refined paraffin-type base oil, a refined naphthenic-type base oil,.or a synthetic hydrocarbon or synthetic nonhydrocarbon oil of lubricating viscosity. As synthetic oils, suitable examples include oils obtained by polymerization of lower molecular weight alkylene oxides, such as propylene oxide and/or ethylene oxide employing alcohol or acid initiators, such as lauryl alcohol or acetic acid. Still other synthetic oils include esters, e.g., di-(Z-ethyl-hexyl)-sebacate, tricresylphosphate and silicate esters, such as tetra-( 2-ethylhexyl)-orthosilicate and hexa-(2-ethylbutoxy)-disiloxane. Forpresent purposes the mineral lubricating oils are In the above test results the oxidizability was obtained by passing oxygen through a 2.8% polymer solution in 130 Neutral Oil at 340F with the amount given indicating liters of oxygen per grams of oil absorbed in 64 hours. The viscosities were determined in terms of Saybolt Universal Seconds at the specified temperature.

The test results show that the polymers of para-tbutyl-alpha-methylstyrene in accordance with the present invention possess surprisingly stable viscosity index improving properties. Although the analogous para-t-' butylstyrene provides viscosity index improvement, it is lowed, in the light of the foregoing disclosure and discussion. without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. The homopolymer of para-t-butyl-a-methylstyrene having an average molecular weight as determined by standard light-scattering measurements in the range of from about 50,000 to about 1,000,000, a molecular structure characterized by recurring styryl units, and a solubility in mineral lubricating oil of at least about 0.1% by weight.

UNITED STATES PATENT AND TRAdEMARK OFFICE CERTIFICATE OF CGRBECTIQN PATENT NO. 2 3,912,700

DA ED I October 14, 1975 INVENTORG) I ROBERT BACSKAI It is certified that error appears m the above-Jdeniified patent and ihai said Letters Patent are hereby COH'ECtGd as shown beiow:

Column 2, line 31 should read -CIi Cl Column 3, line 13, should read (75.2% of theory) line 21 should read (96 8% of theory) Column 4, the TABLE headings should read:

Polymer of Polymer para-tof parabutyl-a- RPM 130 t-butylmethyl- T. E. t re e i f??? v Signed and Scaled this Arrest.

RUTH C. MASON C. MARSHALL DANN Alrostmg Officer mnmissiuncr nj'larenls and Trademarks 

1. THE HOMOPOLYMER OF PARA-T-BUTYL-A-METHYLSTYRENE HAVING AN AVERAGE MOLECULAR WEIGHT AS DETERMINED BY STANDARD LIGHT-SCATTERING MEASUREMENTS IN THE RANGE OF FROM ABOUT 50,000 TO ABOUT 1,000,000, A MOLECULAR STRUCTURE CHARACTERIZED BY RECURRING STYRYL UNITS, AND A SOLUBILITY IN MINERAL LUBR ICATING OIL OF AT LEAST ABOUT 0.1% BY WEIGHT. 